Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) {
        try {
            (new Main()).run();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    private void run() throws IOException {
        PrintWriter out = new PrintWriter(System.out);
        FastScanner in = new FastScanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int[][] map = new int[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                map[i][j] = in.nextInt();
            }
        }
        if (m > n) {
            int k = 0;
            List<Integer> commands = new ArrayList<>();
            for (int i = 0; i < n; i++) {
                int min = map[i][0];
                for (int j = 1; j < m; j++) {
                    if (map[i][j] < min) {
                        min = map[i][j];
                    }
                }
                //System.err.println(min);
                for (int j = 0; j < m; j++) {
                    map[i][j] -= min;
                }
                k += min;
                commands.add(min);

            }
            boolean check = true;
            for (int j = 0; j < m; j++) {
                for (int i = 1; i < n; i++) {
                    check &= (map[i][j] == map[i - 1][j]);
                }
                k+=map[0][j];
                commands.add(map[0][j]);
            }
            if(check){
                out.println(k);
                for(int i=0;i<n;i++){
                    for(int q=0;q<commands.get(i);q++){
                        out.println("row "+(i+1));
                    }
                }
                for(int j=n;j<n+m;j++){
                    for(int q=0;q<commands.get(j);q++){
                        out.println("col "+(j+1-n));
                    }
                }
            }else{
                out.println(-1);
            }
        } else {
            int k = 0;
            List<Integer> commands = new ArrayList<>();
            for (int j = 0; j < m; j++) {
                int min = map[0][j];
                for (int i = 1; i < n; i++) {
                    if (map[i][j] < min) {
                        min = map[i][j];
                    }
                }
                //System.err.println(min);
                for (int i = 0; i<n; i++) {
                    map[i][j] -= min;
                }
                k += min;
                commands.add(min);

            }
            boolean check = true;
            for (int i = 0; i < n; i++) {
                for (int j = 1; j < m; j++) {
                    check &= (map[i][j] == map[i][j-1]);
                }
                k+=map[i][0];
                commands.add(map[i][0]);
            }
            if(check){
                out.println(k);
                for(int j=0;j<m;j++){
                    for(int q=0;q<commands.get(j);q++){
                        out.println("col "+(j+1));
                    }
                }
                for(int i=m;i<n+m;i++){
                    for(int q=0;q<commands.get(i);q++){
                        out.println("row "+(i+1-m));
                    }
                }
            }else{
                out.println(-1);
            }
        }
        out.close();
    }
    private void printMap(int[][] map){
        for(int[] row:map){
            for(int i:row){
                System.err.print(i+" ");
            }
            System.err.println();
        }
    }
    private class Tree {
        Node root;

        Tree(int[] array) {
            this.root = build(array, 0, array.length);
        }

        private Node build(int[] array, int leftBorder, int rightBorder) {
            Node res = new Node(leftBorder, rightBorder);
            if (!res.isLeaf) {
                int mid = (leftBorder + rightBorder) / 2;
                res.leftSon = build(array, leftBorder, mid);
                res.rightSon = build(array, mid, rightBorder);
            } else {
                if (length(res) == 1) {
                    res.sum = array[leftBorder];
                }
            }
            return res;
        }

        void pushBuffer(Node node) {
            if (!node.isLeaf) {
                node.leftSon.addBuffer += node.addBuffer;
                node.leftSon.sum += node.addBuffer * length(node.leftSon);
                node.rightSon.addBuffer += node.addBuffer;
                node.rightSon.sum += node.addBuffer * length(node.rightSon);
            }
            node.addBuffer = 0;
        }

        int length(Node node) {
            return node.rightBorder - node.leftBorder;
        }

        void fixSum(Node node) {
            if (node.isLeaf) return;
            node.sum = 0;
            if (node.leftSon != null) {
                node.sum += node.leftSon.sum;
            }
            if (node.leftSon != null) {
                node.sum += node.leftSon.sum;
            }
        }

        private class Node {
            int leftBorder; //inclusive
            int rightBorder; //not inclusive
            int sum;
            int addBuffer;
            Node leftSon;
            Node rightSon;
            boolean isLeaf;

            Node(int leftBorder, int rightBorder) {
                this.isLeaf = (rightBorder - leftBorder <= 1);
                this.leftBorder = leftBorder;
                this.rightBorder = rightBorder;
                this.sum = 0;
                this.addBuffer = 0;
            }
        }
    }

    private class FastScanner {
        BufferedReader bufferedReader;
        StringTokenizer stringTokenizer;

        FastScanner(InputStream inputStream) {
            this.bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        }

        FastScanner(File file) throws IOException {
            this.bufferedReader = new BufferedReader(new FileReader(file));
        }

        public String next() throws IOException {
            while (stringTokenizer == null || !stringTokenizer.hasMoreTokens()) {
                String line = bufferedReader.readLine();
                if (line == null) return null;
                stringTokenizer = new StringTokenizer(line);
            }
            return stringTokenizer.nextToken();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(this.next());
        }

        public long nextLong() throws IOException {
            return Long.parseLong(this.next());
        }

        public double nextDouble() throws IOException {
            return Double.parseDouble(this.next());
        }

    }
}